1 OS_Mon Release Notes

This document describes the changes made to the OS_Mon application.

1.1 Os_Mon 2.2.5

Improvements and New Features

Cleanups suggested by tidier and modernization of types and specs.

Own Id: OTP-8455

1.2 Os_Mon 2.2.4

Fixed Bugs and Malfunctions

Memsup did not read memory correctly on MaxOSX Snowleopard. This has now been corrected. (Thanks to Joel Reymont)

Own Id: OTP-8211
Removed unused code in cpu_sup.erl.

Own Id: OTP-8226

Improvements and New Features

The documentation is now built with open source tools (xsltproc and fop) that exists on most platforms. One visible change is that the frames are removed.

Own Id: OTP-8201

1.3 Os_Mon 2.2.3

Fixed Bugs and Malfunctions

A missing define in memsup.c caused a build error on IRIX machines. This has now been fixed.

Own Id: OTP-8094

1.4 Os_Mon 2.2.2

Fixed Bugs and Malfunctions

disksup:get_disk_data/0 returned disk volume in bytes instead of kbytes as stated in the documentation. The problem occurred on Windows only and is now corrected.

*** POTENTIAL INCOMPATIBILITY ***

Own Id: OTP-7741

1.5 Os_Mon 2.2.1

Fixed Bugs and Malfunctions

An error in memsup could cause os_mon to report erroneous memory values on windows for ranges of memory between 2GB and 4GB. This have now been fixed.

Own Id: OTP-7944

Improvements and New Features

Added support for dragonfly OS.

Own Id: OTP-7938

1.6 Os_Mon 2.2

Improvements and New Features

The copyright notices have been updated.

Own Id: OTP-7851

1.7 Os_Mon 2.1.8

Fixed Bugs and Malfunctions

A problem with OTP-OS-MON-MIB.mib for 64-bit environments has now been fixed. The mib has been extended with 64-bit memory retrieval counterparts.

In addition, a new function get_os_wordsize/0 has been added in the memsup module

Own Id: OTP-7441
An error in memsup.c caused the compilation to crash on bsd environments. This has now been fixed.

Own Id: OTP-7558

1.8 Os_Mon 2.1.7

Fixed Bugs and Malfunctions

Fixed a build error that occurred on NetBSD (Thanks to Per Hedeland and Raphael Langerhorst)

Own Id: OTP-7505

Improvements and New Features

Memory information in memsup:get_system_memory_data/0 now has additional entries in its property list for linux.

Own Id: OTP-7409 Aux Id: seq10984

1.9 Os_Mon 2.1.6

Fixed Bugs and Malfunctions

System information retrieval on darwin platforms with environments locales not conforming to the C locale caused an error in cpu_sup resulting in process termination.

Own Id: OTP-7320

1.10 Os_Mon 2.1.5

Improvements and New Features

CPU utilization, on linux, is now measured via a port program instead of os:cmd in erlang. This should enhance performance.

Own Id: OTP-7108 Aux Id: OTP-6935

1.11 Os_Mon 2.1.3

Improvements and New Features

Extended memsup memory probing on linux to use a port program to probe memory usage. This is faster then the previous implementation.

Own Id: OTP-6860 Aux Id: seq10616

1.12 Os_Mon 2.1.2.1

Improvements and New Features

Minor Makefile changes.

Own Id: OTP-6689

1.13 OS_Mon 2.1.2

Fixed Bugs and Malfunctions

When the memsup_system_only flag was set to true, a badmatch exception occurred in the function os_mon_mib:get_load/1.

Own Id: OTP-6351 Aux Id: seq10517

1.14 OS_Mon 2.1.1

Fixed Bugs and Malfunctions

Did not build on Mac OS X.

Added support for IRIX. (Thanks to Michel Urvoy and Daniel Solaz.)

Own Id: OTP-6136

Improvements and New Features

disksup: Now using round(T*100) instead of trunc(T*100) when setting the threshold value given a float T.

Own Id: OTP-6153

1.15 Os_Mon 2.1

Fixed Bugs and Malfunctions

In 2.0, a call to alarm_handler:get_alarms/0 was introduced in memsup and disksup. This will lead to problems if the default alarm_handler event handler is not used, however, and the call has now been removed. (Thanks to Serge Aleynikov for pointing this out.)

Own Id: OTP-6029
A bug that in rare cases caused cpu_sup to crash has been corrected.

Own Id: OTP-6102 Aux Id: seq10312

A note on backwards compatibility: The behaviour of OS_Mon 2.0 is backwards compatible under normal operation, but has changed somewhat in error situations: The services do not terminate and the API functions do not raise exceptions in all cases where they did before. Also, in the case where a service does terminate, the exit reason may be different. See below for details.

Fixed Bugs and Malfunctions

A call to a OS_Mon service (cpu_sup, disksup, ...) when OS_Mon is not running, or when the service is not available for the OS, or when the service is not started, will no longer result in an exception. Instead a warning is issued via error_logger and a dummy value is returned, which one is specified in the man pages for the respective service.

The reason is that it should not be necessary for a service to be started on each and every node of a distributed Erlang system for the OS-MON-MIB and other OS_Mon users to work properly.

Own Id: OTP-4332 Aux Id: seq7358
References to the obsolete EVA application in OTP-OS-MON-MIB has been removed.

Own Id: OTP-5699
Setting the option memsup_system_only to true did not work, but would crash the memsup process.

Own Id: OTP-5890 Aux Id: seq10185
cpu_sup:nprocs/0 returned 0 on FreeBsd.

Own Id: OTP-5901
If the OS_Mon service disksup or memsup was restarted, the same alarm could be set twice. Also, set alarms were not cleared when the application was stopped.

Own Id: OTP-5910

Improvements and New Features

Thresholds and time intervals in disksup and memsup are now configurable in run-time.

Own Id: OTP-4246 Aux Id: Seq7230
memsup can now handle systems with more than 4GB of RAM.

Own Id: OTP-5800 Aux Id: seq10130
The entire OS_Mon application (code and documentation) has been reviewed and consequently updated with the goal to make the application more robust, homogeneous and easier to configure.

The behaviour under normal operation is backwards compatible. However, recoverable errors now no longer terminate the affected service (and thus possible the entire application), instead error_logger is used to warn the user if/when such errors occurs. Also, in the case of unrecoverable errors, the services have been made more homogeneous with respect to behavior and exit reasons. See below for more information and refer to the man pages for details.

Port handling has been unified, meaning that if a port program sends garbage or unexpectedly dies, this is now handled the same way by all OS_Mon services, namely immediate process termination with the exit reason {port_error,Garbage} or {port_died,Reason}, respectively.

Application configuration parameter handling has been unified. Bad parameter values are no longer silently ignored (disksup) or cause application termination (memsup, os_sup). Instead a warning is issued and the default value for the parameter is used. Also, some cases where a bad parameter value accidentally could be accepted have been corrected.

Message handling has been unified. Unknown (gen_server-) calls cause process termination, whereas unknown casts and messages are now ignored by all OS_Mon services.

Own Id: OTP-5897
The following changes have been made to the os_sup service:

It is now available on Windows, using nteventlog as backend.

On Solaris, enabling the service (that is, installing a new configuration file for syslogd etc.) can now be done outside the os_sup process. The reason for this is that the Erlang emulator should normally not be run with root privileges, as is otherwise required. The new application configuration parameter os_sup_config must be set to false.

Also, os_sup can now be configured using a new configuration parameter os_sup_mfa to call an arbitrary Erlang function when a message is received from the OS.

Own Id: OTP-5925
The memsup service has been rewritten, replacing the supervised memsup_helper with a linked help process. This gives the memsup process more control and prevents a situation where it gets out of synch with the received memory data and thus possibly returns erroneous results.

Own Id: OTP-5927

1.17 OS_Mon 1.8.1

Fixed Bugs and Malfunctions

cpu_sup:util/0 failed with error reason negative_diff when called the first time on a machine (hw) that had been up for a very long time.

Own Id: OTP-5869 Aux Id: seq10166

1.18 OS_Mon 1.8

Improvements and New Features

The memsup part of the OS_Mon application has been made more stable. If there are (possibly temporary) problems collecting memory data, the interface functions (get_memory_data/0, get_system_memory_data/0) now do not fail, but return the previously collected value, if any, or a dummy value otherwise. Also, a warning message is printed.

*** POTENTIAL INCOMPATIBILITY ***

Own Id: OTP-5798

1.19 OS_Mon 1.7.4

Fixed Bugs and Malfunctions

Corrected several problems in the error handling/error recovery (especially when OS_Mon is starting up).

Own Id: OTP-5559

1.20 OS_Mon 1.7.3

Improvements and New Features

memsup.c will now compile on OpenBSD. (Thanks to Geoff White and Jay Nelson.)

The disksup and cpu_sup modules now work on Mac OS X (tested on Mac OS 10.3.8).

The memsup module should now work on Linux 2.6.* as well as on older Linuxes. (/proc/meminfo has slightly different formats in different releases of Linux.)

Own Id: OTP-5421
Aux Id: OTP-5194, OTP-5228, OTP-5291

1.21 OS_Mon 1.7.2

This version is identical with 1.7.